oliver foster

I get 19 MPG with my 6 inch lifted, running on 37 inch tires, with 4.10 gears in my W-350 '85 crew cab with a getrag, '90 12v, that is bone stock.
My other 3.07 auto '90 12V AUTO '85 W-350 crew cab gets 21 MPG with 33 inch tires.
That is around town driving, with a "not trying to get good mileage" driving style.

Using a light foot, a VE pumped 12V, with a 5 speed and 3.07 gears, could get 25-27 MPG, this would be easier to do if it was a 2wd

jimbo486

You guys don't even wanna know what my '90 is getting with 3.54, 235s, .73 OD gear (6th in NV5600) and being around 5700lbs. Something's going on because I can barely manage to squeeze 15mpg out of it!

#2isgreen

I managed to get 23 once I got my converter in. That made a huge difference. I also keep my tires up around 75 lbs.
I'm hoping the in town goes up soon once I finish up the the he351. Low end boost to match the VE low end grunt.

thrashingcows

Best I've seen with my crewcab running back from Oregon to BC was just shy of 28 MPG. But that was all hwy, and I was only bringing back the truck box I bought down there.

Around town I usually see about 20-21mpg.

I'm interested to see what my mileage goes to once I do the 4x4 conversion, since the diffs I have inthe donor 93 are 4.10's. If it sucks too bad then I will switch back to 3.54's.

Mick-e

I'm with you. I filled up today and did the math and i got 15.6. That's not uncommon for my around town. I just recently turned my pump up, and it's making way more power for sure, but I was hoping with more fuel earlier I would actually see an increase in MPG.
The best I ever get is 19 on the highway nursing it at 65mph.
How are you guys getting 23?
I know I've got big tires, but I figured I'd be doing better.

dzl_damon

Your tires and automatic are killing you. If you have some high mileage on a stock torque converter, you are loosing a lot in that.

I regularly get 20-21mpg in the 89 2wd with a very tight transmission and 3.07's I've gotten 23mpg on occasion.

My best in the dually was about 18 or 19 when I first got it on stock tires and less tired transmission. I get about 15 with it now if I'm easy on it. Tires and transmission.

NE frmhnd

You might check your odometer against the mile markers sometime you run a fair distance on the interstate. My speedometer runs about 9% behind actual miles.

TIMMY22

My 5spd 2WD gets 21-23 highway. That's cruising at about 70. I can roll out 600 mi consistently before the fuel light comes on.

jbawden

I agree, inaccuracies in the odometer would probably explain a portion of the claims of extreme mileage. I know this thread is from 2008, but the best part of any video or controversial article on the internet is the comment section. If someone posted a video on youtube of a baby being rescued someone would dislike it and post some a-hole comment...sort of like how message board works

NE frmhnd

Any time a significant change in tire size is made, it throws off the speed and mileage. I'd step mine up a little but doubt I can find much taller of a tire that's not real wide and stick with my stock wheels.

My speedomoter reads 5% slow, running a mile with the speedometer at 60 takes 57 seconds. And I've estimated my odometer shows 9% behind actual mileage.

mtdoragary

Yep; I consistently get five miles per gallon better than my wife in all our vehicles. The other big keys are tire pressure, tire width, and wind resistance. jacked up trucks suffer. I'd like to have had fender skirts when I had duallies, but could never find them. I also wonder about adapting those wind channeling panels that you see under over the road trucks these days.

mtdoragary

The most ACCURATE way to figure mileage is on a long trip using your GPS to measure mileage traveled. And even the GPS shorts you on mileage when you're on hills. That's what map mileage is always shorter than actual mileage travelled. Map mileage is figured as though all roads were flat! So NOBODY REALLY knows what their mpg is - there are just too many inaccurate variables..... even the gas pumps are inaccurate these days with no money to pay inspectors and pumps going years without inspection. My Audi TDI says it's getting 42 all around mpg and better than 50 on the highway. I don't know how far off that is, but even if it's optimistic by 10mpg, I wouldn't trade it for a dozen Priuses!

whosdunit

Since " THEY " took the lead out of the gas ( I know diesel don't have lead) ,it seems to have went to someones "foot". Slower acel. on the peddle makes better mpg.

whosdunit.